Gastroesophageal Reflux and Apnea of Prematurity: No Temporal Relationship

ABSTRACT. Objective. A relationship between gas-troesophageal reflux (GER) and apnea of prematurity (AOP) has long been suspected but is difficult to prove because most GER in this age group is nonacidic and thus undetectable by pH monitoring, the current stan-dard for GER detection. The new multiple intraluminal impedance (MII) technique allows pH-independent re-flux detection via changes in impedance caused by a liquid bolus inside the esophagus. We used this tech-nique to investigate whether there is a temporal relation-ship between GER and AOP and whether GER occurs predominantly before a cardiorespiratory (CR) event. Methods. Nineteen infants with AOP (median gesta-tional age at birth: 30 weeks; range: 24–34; age at study: 26 days [13–93]) underwent 20 6-hour recordings of MII, breathing movements, nasal airflow, electrocardiogram, pulse oximeter saturation, and pulse waveforms. MII signals were analyzed, independent of CR signals, for reflux episodes (RE), defined as a fall in impedance in at least the 2 most distal channels. CR signals were ana-lyzed for CR events, ie, apneas of>4-second duration, desaturations to <80%, and falls in heart rate to <100/ min. A temporal relationship between an RE and a CR event was considered present if both commenced within 20 seconds of each other. Results. There were 2039 apneas (median: 67; range